They're a rite of passage for every young person in Ireland.
Whether it was in the local tennis club or community centre, – you'd look forward to it for months, wear questionable outfits and leave looking like you'd just done a workout.
But things have changed. Big time.
Gone are the days of a single DJ on a stage, black plastic bags covering the community centre windows at 7pm in the evening to keep the light out, cloakrooms full of sleepover bags and parents queueing outside to collect their children.
THIS is what teenage discos apparently look like nowadays.
Pulse Dublin held a New Year's Eve party in the Tivoli Theatre, and made this 'after-movie' of the night. Take a look and try not to feel absolutely ancient.